1. Field of the Invention
The present invention relates to a four-direction switch device suitably used for a vehicle keyless entry device.
2. Description of the Prior Art
Drawings of a conventional four-direction switch device are described below. FIG. 6 is a plan view showing a conventional four-direction switch device. FIG. 7 is a sectional view taken along the line 7xe2x80x947 of FIG. 6.
A box-shaped upper case 51 made of a synthetic resin material has an upper wall 51a, a side wall 51b which is elongated almost vertically from an outer circumferential edge of the upper wall 51a and surrounds the switch device, and a through hole 51c provided at a nearly central portion of the upper wall 51a. 
A holding member 52 made of a synthetic resin material is formed into the shape of a nearly square flat plate and four rectangular through holes 52a are formed in positions of a cross shape toward four outer circumferential sides from the central position of the holding member 52. The holding member 52 is fastened within the through hole 51c of the upper case by a proper means to block the through hole 51c. 
Plural (four) operation knobs 53 made of a synthetic resin material are in the shape of a nearly rectangular flat plate, and on the surfaces of the respective operation knobs 53 are drawn icons 53a indicating specific operations such as a door open indication symbol, a door lock indication symbol, a trunk open indication symbol, and a panic operation indication symbol. The four operation knobs 53 are disposed within the four through holes 52a. The respective icons 53a are drawn one for each of the operation knobs 53. On the back of the operation knobs 53 is formed an engaging part 53b protruding outward.
An elastic cover 54 made of an elastic rubber material, which is similar to a dome in shape, has an upper wall 54a, a side wall 54b elongated curvedly from an outer circumferential edge of the upper wall 54a downward, flanges 54c protruded orthogonally to the side wall 54b from an open end thereof, four engaging parts 54d protruding from an outer surface of the upper wall 54a outward and provided in positions of a cross shape, and four pressing parts 54e protruding from an inner surface of the upper wall 54a inward and provided in positions respectively opposite to the four engaging parts 54d. 
To the engaging parts 54d of the elastic cover 54, engaging parts 53b of the operation knobs 53 are coupled by such a proper means as snaps in a snap leg (not shown) provided on the engaging parts 54d in an indention (not shown) of the operation knobs 53. By this coupling, the operation knobs 53 are attached to the elastic cover 54.
A pushbutton switch 55 has a box-shaped housing 55a housing a movable contact (not shown), a fixed contact (not shown), and the like, and a pushbutton 55b provided protrusively from the upper surface of the housing 55a outward under pressure of the movable contact (not shown) and a spring member (not shown). Four of the pushbutton switches 55 are disposed, and the respective pushbuttons 55b of the pushbutton switches 55 have a nearly equal press operation power by dint of the movable contact (not shown) and the spring members (not shown).
The four pushbutton switches 55 are disposed opposite to the four pressing parts 54e of the elastic cover 54.
A printed wiring board 56 is in the shape of a nearly rectangle flat plate, and on the surface of the printed wiring board 56 is formed a required circuit pattern (not shown). On the printed wiring board 56 are disposed in positions of a cross shape the four pushbutton switches 55.
The printed wiring board 56 and the pushbutton switches 55 are housed within the elastic cover 54.
A box-shaped lower case 57 made of a synthetic resin material has a nearly rectangular bottom wall 57a, a side wall 57b which is elongated almost vertically from an outer circumferential edge of the bottom 57a and surrounds the switch device, and steps 57c provided at open ends of the side wall 57b. The lower case 57 and the upper case 51 are integrally incorporated with the flanges 54c of the elastic cover 54 being interposed therebetween.
Next, the operation of the conventional four-direction switch device is described.
First, when a required press power is applied to one operation knob 53 on which an icon 53a indicating a specific operation is drawn, the operation knob 53 is moved downward by the press power, and the elastic cover 54 is distorted at one location by the movement. By the pressing parts 54e of the distorted elastic cover 54, the pushbutton 55b of one pushbutton switch 55 is operated against a movable contact and a spring member and the pushbutton switch 55 goes on. During this operation, operation power by the moving contact and the spring member in one pushbutton switch 55 and operation power of the elastic cover 54 by distortion at one location together enable the operation knob 53 to be operated with a small press power.
When the press power to the operation knob 53 is removed, the operation knob 53 returns to its original position by the self-return force of the pushbutton 55b of the pushbutton switch 55 and the self-return force of the elastic cover 54, and the pushbutton switch 55 is turned off when the operation knob 53 returns to its original position.
When the operation knobs 53 on which the other three icons 53a are drawn are respectively applied with press power, the same operation as the above described operation in one pushbutton switch 53 is performed. Even by press power to any operation knob 53, the operation knob 53 can be operated with the same small press power by dint of operation power of one pushbutton switch 55 and operation power of the elastic cover 54 by distortion at one location. All press powers to the four operation knobs 53 are equalized.
In other words, in a normal condition, since press power of one pushbutton switch 55 operated by an operation knob 53 in which an icon 53a indicating the operation of a panic operation indication symbol is drawn is almost equal to press power of the pushbutton switches 55 respectively operated by the other three operation knobs 53 in which other icons 53a are drawn, the operation knob 53 in which the icon 53a indicating the operation of a panic operation indication symbol is drawn will be easily and carelessly operated.
As has been described above, in a conventional four-direction switch device, since press powers to the four operation knobs are almost equal, if an operation knob of panic operation is carelessly operated, such malfunctions that, for example, a horn is sounded or a light blinks are liable to occur.
The present invention provides a four-direction switch device that is almost free of careless operations on operation knobs thereof.
A four-direction switch device of the present invention comprises: a case; plural pushbutton switches housed in the case; and one operation member that is supported by the case to be tiltable in four directions and operates the pushbutton switches by tilt operations in the respective directions, wherein the operation member can tilt to first and second tilt positions that are opposite to each other with respect to a tilt center, and third and fourth tilt positions that are orthogonal to the first and second tilt positions and are opposite to each other with respect to the tilt center, and the operation member has an operation power increasing means for producing greater operation power for a tilt to the fourth tilt position than for tilts to the first, second, and third tilt positions during tilt operations on the operation member.
With the construction, since tilt operation power to one tilt position of the operation member is greater than tilt operation power to other three tilt positions, there is a difference in the magnitude of tilt operation power, so that a four-direction switch device almost free of careless operations can be provided which can explicitly tell the operator a tilt position requiring the great tilt operation power.
The four-direction switch device of the present invention has first, second, and third pushbutton switches operated by the operation member, wherein one pushbutton switch is operated in each of the first, second, and third tilt positions, wherein two of the pushbutton switches are operated in the fourth tilt position, and wherein the operation power increasing means is constituted by operation power with which the two pushbutton switches are operated.
With the construction, since the four-direction switch device can be configured with three pushbutton switches, the number of parts can be reduced and the inexpensive four-direction switch device having a simple construction can be provided in which the operation power increasing means is constituted by operation power with which the two pushbutton switches are operated.
In the four-direction switch device of the present invention, the first pushbutton switch is placed on a line passing through the tilt center at a side of the third tilt position, the second pushbutton switch is placed in a middle position between the first tilt position and the fourth tilt position, the third pushbutton switch is placed in a middle position between the second tilt position and the fourth tilt position, when the operation member is operated to tilt to the fourth tilt position, the two second and third pushbutton switches are operated at the same time, and the operation power increasing means is constituted by operation power with which the two second and third pushbutton switches are operated.
By this construction, a four-direction switch device can be provided which enables three pushbutton switches to be operated without fail.
In the four-direction switch device of the present invention, each pushbutton switch is constructed to operate by dint of pressure opposing a press of a spring movable contact or/and a press of a spring member energizing the pushbutton, and the operation power increasing means is constituted by the pressure against the two pushbutton switches.
By this construction, since the operation power increasing means has a simple construction, the number of parts can be reduced and an inexpensive four-direction switch device can be provided.
In the four-direction switch device of the present invention, an elastic cover made from rubber is disposed to cover the pushbutton switches between the operation member and the plural pushbutton switches, the pushbutton switches are operated via the elastic cover by tilting the operation member, and during a fourth tilt operation, the elastic cover is formed to distort in at least two locations which are opposite to two pushbutton switches, to use the distortion of the elastic cover as the operation power increasing means.
By this construction, since the operation power increasing means has a simple construction, the number of parts can be reduced and further an inexpensive four-direction switch device can be provided.
The four-direction switch device of the present invention is constructed so that a panic operation is performed by operating the operation member for the fourth tilt operation, which is provided with the operation power increasing means. With this construction, a four-direction switch device almost free of careless panic operations can be provided.